Updated

Sacramento city officials reached a preliminary agreement Saturday night for a new downtown arena with an investment group that hopes to keep the Kings from moving to Seattle.

Sacramento Mayor Kevin Johnson first announced the deal on his Twitter account. A few hours later, the city released the details of the non-binding term sheet.

The group includes Silicon Valley software tycoon Vivek Ranadive, 24 Hour Fitness founder Mark Mastrov and billionaire Ron Burkle. The City Council is planning to vote on the agreement Tuesday.

"Once again, we're proving the strength of our market — both as host to an NBA team, but as an emerging region with global potential," Johnson said.

The city of Sacramento plans to contribute $258 million to the $447 million project, mostly by leasing out parking garages and land. The other $189 million will come from the investment group.

Johnson said the deal will avoid new taxes and ensure a net impact to the city's general fund.

"This is a monumental project that will redefine the Downtown Plaza and revitalize our urban core," City Manager John Shirey said in a statement. "This project is about providing a regional attraction and creating economic development opportunities that will retain and create thousands of jobs, bring people downtown, increase property and sales tax — all of which will contribute to our city's vitality."

Sacramento is hoping to block a bid by group that has a pending purchase agreement to buy the Kings from the Maloof family, move the team to Seattle and restore the SuperSonics name. That group, led by hedge-fund manager Chris Hansen and Microsoft Chief Executive Steve Ballmer, has had a deal to acquire a 65 percent stake in the team for $341 million since January.

The NBA Board of Governors is expected to make a decision by mid-April. If league blocks the Seattle deal, the Maloofs would still have to agree to sell to any other group.